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Black smoke from linea

Discussion in 'Service Center Reviews' started by KKAUL, Sep 3, 2015.

  1. KKAUL

    KKAUL Amatore

    Messages:
    205
    delhi
    Grande Punto 1.3
    @Anup

    Can You please elaborate how will a clog injector will lead to a black smoke and we are talking of Bosch injector which has internal by pass in case of clogging.
    As far as I can understand black smoke is due to incomplete combustion
    1) Either air is less
    2) Either Fuel is more (eventually not in atomised form)
    I thought very hard but am unable to understand how you are linking it.
  2. Anup

    Anup Regolare

    Messages:
    303
    Bangalore
    Bangalore
    Grande Punto 1.3
    @KKAUL, there are many draw back of cloged injector, it can lead to stalled engine if all of the injectors are clogged.

    Now say if you have 1 or 2 injectors clogged, the other injectors are spraying fuel which leads to low FE, and fuel which is eventually sprayed from the clogged injector will be left un burned inside the chamber, the injector cleaner makes the fuel viscose and makes fuel to burn more which eventually will remove the clogging of the injectors.
  3. KKAUL

    KKAUL Amatore

    Messages:
    205
    delhi
    Grande Punto 1.3
    @Anup

    I am unable to understand your point of how come the Fuel is left unburned.
    Now I will write the sequence and Please indicate where I am faltering.

    The Firing cycle starts and assuming 4 cylinder engine with 4 injectors out of which say 3 are clogged. The definition of clogged is that the the Front part nozzle which is exposed to the chamber having 2,4 to 6 hole depending upon the design are filled with something which results in blocking the supply of fuel to the chamber.
    The injector we are using are Peizo type that of Bosch.
    Assuming Working of a simple bosch piezo injector that it has 2 ports 1 connected to the rail and second is the excess fuel pipe connected indirectly to the tank.
    Now suppose Inj 1 , 2, 3 are clogged what will happen .
    The sequence
    The rail is pressurised
    piezo 1 is activated by ECU it opens the port connected to the rail and thus connecting spray nozzle . Since the nozzle is choked no fuel is entering the chamber thus no combustion. The fuel which entered the injector will get bypassed through the excess port to the tank.Similar would be case with chamber 2 and 3. Only chamber 4 will have combustion.
    In this case no Fuel was left in the chamber. The injector Fire 1 by 1 as per the Cam shaft timings thus only chamber 4 will have combustion with 0 fuel in chamber 1,2,3 though conditions are fully met for healthy combustion as far as air supply and compression is considered in chamber 1,2 and 3
    Please indicate where I am unable to understand your point.

    Now I will try to create a condition for black smoke which I think You are having in back of your mind which I could get from your post may be I am wrong or right.

    Injectors are not clogged but worn out that means the the spray nozzle holes diameter have increased due to adulterated fuel or over heating.
    In this case the nozzle will inject more amount of fuel than required in the chamber thus leading to incomplete combustion and Fuel being passed on to exhaust pipe and combustion taking place in exhaust.
    In this case the nozzle will have another severe effect
    The hole profile governs the output spray profile whether it is a solid cone or a hollow cone to utilize maximum combustion projected area on the piston. If the hole is damaged the full area of the piston will not be under stress and it will result in hot spot on the piston.The nozzle will have a tendency to retain a drop of Fuel (exaggerated) and that will drop into the chamber when not required thus leading to black smoke.

    Honestly speaking a choked injector might give a better FE than in healthy condition because you are using less fuel to cover same distance.
    about injector cleaner claims:
    The company who sells these product tell them to prove that they can clean the injectors. These are usually again blend of solvents mostly having Turpentine oil base and frequent use might lead to damage only than good.

    I hope I have written it correct but if you still feel that I have faltered somewhere your suggestions would always be welcome.
    Deepak likes this.
  4. Deepak

    Deepak Regolare

    Messages:
    459
    KA-30
    Bengaluru
    Punto Evo 1.3 90 HP
    Just curious on how a clogged injector can cause smoke from the exhaust? If an injector was not injecting fuel the engine would miss fire on that cylinder and only air would come out of the cylinder. Smoke from the exhaust is unburned fuel, if injectors themselves are clogged, how fuel can enter inside the cylinder:banghead:
  5. Turbothinghy

    Turbothinghy Superiore

    Messages:
    833
    Pune
    Punto Evo 1.3 90 HP
    I have a very stupid question in my mind. How do we get to know that the car is emitting black or white smoke while driving??
    Aditya0027 likes this.
  6. Anup

    Anup Regolare

    Messages:
    303
    Bangalore
    Bangalore
    Grande Punto 1.3
    @KKAUL sorry buddy cannot do any further write up on this, may be I had a small write up and couldn't cover more points anyway no issues I am satisfied with using so called solvents as I know I can feel the difference...
  7. R Rajesh

    R Rajesh Novizio

    Messages:
    49
    Salem
    salem
    Retro / Classic FIAT
    You May check wheather there is any air pressure leakage around the hose connected from the turbo to after cooler and the hose from the after cooler to engine.this may be identified by observing a isss noise while pressing suddenly the accelerator.Kindly check int it.
  8. rajks

    rajks Amatore

    Messages:
    146
    Bangalore
    Black smoke is seen from my Linea MJD when it is pushed hard in 2nd or 3rd gear, and I notice that the smoke surge is only for a second or two. Since the smoke surge happens only during hard pedaling I thought this is normal as there wasn't enough time to burn it out. Other factors like FE and pickup are normal, now is it common for MJDs to produce occasional bout of black smoke?

    Thanks.
  9. Deepak

    Deepak Regolare

    Messages:
    459
    KA-30
    Bengaluru
    Punto Evo 1.3 90 HP
    Yes black smoke is common on hard acceleration. And hard acceleration is not adviced.

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